CN110850680A - Curable composition, display element, and method for forming cured film - Google Patents

Abstract

The invention aims to provide a curable composition, a display element and a method for forming a cured film, wherein the cured film has high hardness and excellent solvent resistance even though the film is obtained by a curing and calcining process at 200 ℃ or below while the storage stability and the radiation sensitivity are improved. The invention for solving the above problems is a curable composition containing (A) a compound having a polymerizable group, (B) a photosensitizer, and (C) a thermally active delayed fluorescence compound.

Description

Curable composition, display element, and method for forming cured film

Technical Field

The invention relates to a curable composition, a display element and a method for forming a cured film.

Background

Display elements such as liquid crystal display elements, organic electroluminescence (el) elements, and electronic paper elements are provided with a protective film for preventing deterioration or damage of electronic components such as touch panels, an interlayer insulating film for maintaining insulation between wirings arranged in a layered manner, and a cured film such as a planarizing film for improving an aperture ratio. In the formation of such a cured film, a radiation-sensitive curable composition is used, and for example, a cured film is obtained by forming a coating film of the curable composition on a substrate, exposing the substrate to light through a photomask having a predetermined pattern, developing the substrate with a developer to remove unnecessary portions, and then heating (post-baking).

The curable composition is required to have a viscosity not too high even after long-term storage (storage stability) and to have good radiation sensitivity. In addition, a cured film obtained from the curable composition is required to have high hardness and excellent resistance (solvent resistance) to a solvent used in a subsequent step of forming the cured film.

Further, regarding such a cured film formation, in general, from the viewpoint of reducing environmental load and preventing thermal deterioration of dyes or organic light-emitting bodies which are insufficient in response to plastic substrates or heat resistance, a curing and baking process at 200 ℃ or less has been studied from the viewpoint of a curing and baking process at 200 ℃ or more (japanese patent laid-open No. 2013-237750).

However, it is difficult for the curable composition described in the above publication to form a cured film having high hardness and excellent solvent resistance even in a low-temperature baking process while improving storage stability and radiation sensitivity.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2017-126068

Patent document 2 Japanese patent application laid-open No. 2011-257537

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a curable composition which can form a cured film having high hardness and excellent solvent resistance even in a film obtained by a curing and firing process at 200 ℃.

Means for solving the problems

The present inventors have made diligent studies to solve the above problems. As a result, the present inventors have found that the above problems can be solved by a curable composition having the following structure, and have completed the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention for solving the above problems is as follows:

(1) a curable composition comprising [ A ] a compound having a polymerizable group, [ B ] a photosensitizer and [ C ] a thermally active delayed fluorescence compound.

(2) A curable composition wherein the thermally active delayed fluorescence compound (C) is a compound represented by the following formula (1) or formula (2).

[ solution 1]

In the formulae (1) and (2), R¹To R⁷At least one of them represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a phenyl group, a tolyl group, a naphthyl group, a cyano group, or a group represented by the formula (X).

In the formula (X), R²¹To R²⁸Each independently represents a hydrogen atom or a substituent. Wherein at least one of < A > or < B > is satisfied.

＜A＞R²⁵And R²⁶Together form a single bond.

＜B＞R²⁷And R²⁸Together form a substituted or unsubstituted benzene ring.

(3) A curable composition characterized in that the formula (X) represents a 9-carbazolyl group, a 3, 6-di (tert-butyl) -9-carbazolyl group, a substituted or unsubstituted 1,2,3, 4-tetrahydro-9-carbazolyl group, a substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group.

(4) The curable composition wherein the polymerizable group of the compound (A) having a polymerizable group is at least one member selected from the group consisting of an epoxy group, a vinyl group and a (meth) acryloyl group.

(5) A curable composition further comprising (D) a binder resin.

(6) The photosensitive agent (B) is a curable composition selected from an acid generator, a base generator, and a radical polymerization initiator.

(7) One such sensitizer is in turn a curable composition comprising a condensed ring free radical polymerization initiator.

(8) A curable composition having a content ratio of (C) a thermally active delayed fluorescence compound in the range of 0.1 to 3 with respect to the total content of (B) a photosensitizer.

(9) A method for forming a cured film includes the following steps.

A step of forming a coating film of the curable composition on a substrate, and a step of exposing the coating film or heating the coating film at 80 ℃ or higher and 150 ℃ or lower.

(10) A display element having a cured film obtained by the method for forming a cured film.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail, but not limited thereto.

< curable composition >

Curable composition of the invention: the curable composition contains (A) a compound having a polymerizable group, (B) a photosensitizer, and (C) a thermally active delayed fluorescence compound.

The curable composition contains [ A ] a compound having a polymerizable group, [ B ] a photosensitizer, and [ C ] a thermally active delayed fluorescence compound, and thus can improve storage stability and radiation sensitivity, and a cured film formed by a low-temperature firing process can be formed into a cured film having high hardness and excellent solvent resistance.

Thermally active Delayed Fluorescence (also referred to as TADF) refers to a phenomenon in which light is emitted through conversion from triplet excitons to singlet excitons, which does not occur in general, is Activated by heat, and exhibits a longer Fluorescence lifetime than a general fluorescent material. The organic EL material has been drawing attention as a next-generation organic EL light-emitting material capable of improving light conversion efficiency. In the present invention, it was found that by using a compound causing TADF in combination with a photosensitizer having a similar structure, a hardening reaction proceeds in a temperature region where TADF occurs, thereby forming a hardened film.

In general, a cured film is formed by forming a coating film from a curable composition, exposing to light to [ B ] a photosensitizer to generate a polymerization initiator species, and initiating a crosslinking reaction of [ A ] a compound having a polymerizable group. Further, the crosslinked structure formed in the ordinary curing process is heated to 200 ℃ or higher to obtain a stronger crosslinked structure. The cured film is usually formed by photo-curing or thermal curing.

However, in the present invention, instead of the high-temperature heating and calcining process at 200 ℃ or higher, the hardening reaction is performed by using the TADF effect. A photosensitizer having a close energy order of singlet excited states in which a TADF effect occurs at a temperature higher than room temperature (50 ℃ to 100 ℃) is used in combination.

It is considered that the material which spontaneously generates the TADF effect generates electron transfer to the photosensitizer, the photosensitizer is excited to generate the polymerization initiator species, and the curing reaction proceeds again by the generation of the polymerization initiator species. From this, it is presumed that by using (C) the thermally active delayed fluorescence compound, a cured film can be formed without performing a high-temperature process.

First, the compound [ A ] having a polymerizable group contained in the curable composition of the present invention will be described.

[ A ] Compound having polymerizable group ]

The compound having a polymerizable group [ a ] of the present invention is a compound having one or more polymerizable groups in one molecule, and the polymerizable group is at least one selected from the group consisting of an epoxy group, a vinyl group, and a (meth) acryloyl group. [A] The compound having a polymerizable group may be a monomeric compound or a polymer.

The polymerizable group of the monomeric compound of the compound having a polymerizable group [ a ] is preferably a polymerizable compound having a (meth) acryloyl group or vinyl group from the viewpoint of radical polymerizability. By including these compounds, the hardness of the obtained cured film can be increased, and the adhesion of the cured film to the substrate can be improved.

Specific examples of such compounds include the following compounds.

For example, monofunctional, difunctional or trifunctional or higher (meth) acrylate is preferable in terms of improvement in polymerizability and strength of the cured film to be formed. In addition, a compound having a vinyl group can be used as a vinyl sulfide derivative, a (meth) acrylate derivative, a vinyl sulfoxide derivative, or a vinyl sulfone derivative. These compounds are preferable in that the sensitivity can be improved or the storage stability of the curable composition can be favorably maintained.

Examples of the monofunctional (meth) acrylate include: 2-hydroxyethyl (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, (2- (meth) acryloyloxyethyl) (2-hydroxypropyl) phthalate, omega-carboxy polycaprolactone mono (meth) acrylate, and the like. Examples of the commercial products include: aronix (registered trademark) M-101, Aronix (registered trademark) M-111, Aronix (registered trademark) M-114, and Aronix (registered trademark) M-5300 (manufactured by Toyo Seisakusho Co., Ltd.); KAYARAD (registered trademark) TC-110S, KAYARAD (registered trademark) TC-120S (manufactured by japan chemicals (stock) above); costate (Viscoat)158, costate (Viscoat)2311 (manufactured by osaka organic chemical industry (inc.) above), and the like.

Examples of the difunctional (meth) acrylate include: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (acrylate), tetraethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, fluorene-based diacrylate, and the like. Examples of the commercial products include: aronix (registered trademark) M-210, Aronix (registered trademark) M-240, Aronix (registered trademark) M-6200 (manufactured by Toya Synthesis (stock), supra), KayaRAD (KAYARAD) (registered trademark) HDDA, KayaRAD (KAYARAD) (registered trademark) HX-220, KayaRAD (KAYARAD) (registered trademark) R-604 (manufactured by Nippon Chemicals (stock), supra), Biscoat (Viscoat)260, Biscoat (Viscoat)312, Biscot (Viscoat) HP 335 (manufactured by Okaka organic Chemicals (stock), Laget Acrylate (Light Acrylate)1,9-NDA (Co., Ltd.), and Osogel (SOOGL) (EA-0200, Osaka chemical Co., Ltd.), etc.

Examples of the trifunctional or higher (meth) acrylate include: trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate;

a mixture of dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate;

ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, tris (2- (meth) acryloyloxyethyl) phosphate, succinic acid-modified pentaerythritol tri (meth) acrylate, succinic acid-modified dipentaerythritol penta (meth) acrylate, tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, a mixture of Ethylene Oxide (EO) isocyanurate-modified diacrylate and isocyanurate EO-modified triacrylate;

and polyfunctional urethane acrylate compounds obtained by reacting a compound having a linear alkylene group and an alicyclic structure and having two or more isocyanate groups with a compound having one or more hydroxyl groups in the molecule and having three, four, or five (meth) acryloyloxy groups.

Examples of the commercially available product of the trifunctional or higher (meth) acrylate include: aronius (Aronix) (registered trademark) M-309, Aronix (registered trademark) M-400, Aronix (registered trademark) M-405, Aronix (registered trademark) M-450, Aronix (registered trademark) M-7100, Aronix (registered trademark) M-8030, Aronix (registered trademark) M-8060, Aronix (registered trademark) RADD TO-1450 (manufactured by Toya Synthesis (Strand), Kayada (KAYA) (registered trademark) TMPTA, Kayada (registered trademark) DPHA, Kayada (KAYA) (registered trademark) YAA-YA20, Kayada (KADPC) (registered trademark) DPCA-30, Karada (registered trademark) YA-120, and KARADA (registered trademark) DPC-120, Examples of the "KAYARAD" (registered trademark) DPEA-12 (manufactured by japan chemical (stock) above), boster (Viscoat)295, boster (Viscoat)300, boster (Viscoat)360, boster (Viscoat) GPT, boster (Viscoat)3PA, boster (Viscoat)400 (manufactured by osaka organic chemical industry (stock) above), and a "New Frontier" (registered trademark) R-1150 (manufactured by first industrial pharmaceutical (stock)) and a "KAYARAD" (registered trademark) DPHA-40H (manufactured by japan chemical (stock)) as a product containing a polyfunctional urethane acrylate compound.

Of these, particularly preferred are those containing ω -carboxy polycaprolactone monoacrylate, 1, 9-nonanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate;

a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate;

a mixture of tripentaerythritol hepta (meth) acrylate and tripentaerythritol octa (meth) acrylate;

commercially available products of ethylene oxide-modified dipentaerythritol hexaacrylate, polyfunctional urethane acrylate compounds, succinic acid-modified pentaerythritol triacrylate, and succinic acid-modified dipentaerythritol pentaacrylate.

As the compound having a vinyl group, there can be mentioned: styrene, vinylnaphthalene, 1, 3-divinylnaphthalene, 1, 4-divinylnaphthalene, 1, 5-divinylnaphthalene, 1, 6-divinylnaphthalene, 1, 7-divinylnaphthalene, 2, 3-divinylnaphthalene, 2, 6-divinylnaphthalene, 2, 7-divinylnaphthalene, 1,2, 4-trivinylnaphthalene, 1,2, 6-trivinylnaphthalene, 1, 3-divinyl-6-methoxy-naphthalene, 1, 3-divinyl-6-methyl-naphthalene, 1, 3-divinyl-6-chloro-naphthalene, 1, 2-divinyl-6-ethoxy-naphthalene, 1-vinyl-5-methoxy-naphthalene, alpha-vinylnaphthalene, 1-vinylnaphthalene, 2-vinylnaphthalene, and the like.

It is also possible to use compounds having a vinyl group in the vinyl sulfide derivatives, (meth) acrylate derivatives, vinyl sulfoxide derivatives or vinyl sulfone derivatives. Specific examples of such compounds include: vinyl sulfides, phenyl vinyl sulfoxides, divinyl sulfones, phenyl vinyl sulfones, bis (vinylsulfonyl) methane, and the like.

The above-mentioned single-quantum compounds may be used alone or in combination of two or more. The lower limit of the amount of the monomeric compound used in the curable composition of the present invention is not particularly limited, and is, for example, 50% by mass, preferably 60% by mass in terms of solid content. On the other hand, the upper limit thereof is preferably 99% by mass, and more preferably 95% by mass.

When the compound having a polymerizable group [ a ] is a polymer, a polymer containing a constituent unit having a (meth) acryloyloxy group in the polymer (hereinafter, also referred to as "a polymer") can be used. Such polymers may be used in combination with monomeric compounds, in which case the polymers may also be used as binder resins.

The constituent unit having a (meth) acryloyloxy group can be formed, for example, by the following method or the like: a method of reacting (meth) acrylic acid with an epoxy group in a polymer, a method of reacting a (meth) acrylate having an epoxy group with a carboxyl group in a polymer, a method of reacting a (meth) acrylate having an isocyanate group with a hydroxyl group in a polymer, and a method of reacting a (meth) acrylic acid with an acid anhydride site in a polymer.

[a] The polymer can be obtained, for example, by: the compound (a1) which can provide a carboxyl group-containing constituent unit and the compound which can provide the other constituent unit are copolymerized in a solvent in the presence of a polymerization initiator. Can be produced by reacting a compound (a2) which provides a constituent unit containing a (meth) acryloyl group with a constituent unit containing a carboxyl group.

[ (a1) Compound ]

Examples of the compound (a1) include: unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, anhydrides of unsaturated dicarboxylic acids, mono [ (meth) acryloyloxyalkyl ] esters of polycarboxylic acids, and the like. Examples of the unsaturated monocarboxylic acid include: acrylic acid, methacrylic acid, crotonic acid, and the like. Examples of the unsaturated dicarboxylic acid include: maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and the like. Examples of the anhydride of the unsaturated dicarboxylic acid include anhydrides of the compounds exemplified as the dicarboxylic acid. Examples of mono [ (meth) acryloyloxyalkyl ] esters of polycarboxylic acids include: mono [ 2- (meth) acryloyloxyethyl ] succinate, mono [ 2- (meth) acryloyloxyethyl ] phthalate and the like.

Among these (a1) compounds, acrylic acid, methacrylic acid, and maleic anhydride are preferable, and acrylic acid, methacrylic acid, and maleic anhydride are more preferable in terms of copolymerization reactivity, solubility in an alkaline aqueous solution, and easiness of acquisition. These (a1) compounds may be used alone or in combination of two or more.

The proportion of the compound (a1) used is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, based on the total amount of the constituent monomers of the polymer (a). By setting the use ratio of the compound (a1) to 5 to 30% by mass, the solubility of the polymer in an alkaline aqueous solution can be optimized.

The (meth) acrylate having an epoxy group is an unsaturated compound containing an epoxy group, and examples of the epoxy group include an oxetanyl group (1, 2-epoxy structure) and an oxetanyl group (1, 3-epoxy structure). Specifically, there may be mentioned: glycidyl (meth) acrylate, 3- (meth) acryloyloxymethyl-3-ethyloxetane, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 3, 4-epoxytricyclo [5.2.1.0 ] meth (acrylic acid)^2.6]Decyl ester, tris (4-hydroxyphenyl) ethane triglycidyl ether, and the like.

The polymer of the present embodiment can be produced by a known method, and can be synthesized by a method disclosed in, for example, Japanese patent laid-open Nos. 2003-222717, 2006-259680, 07/029871 pamphlet, 5-19467, 6-230212, 7-207211, 09-325494, 11-140144, 2008-181095 and the like.

[a] The structural unit having a (meth) acryloyloxy group of the polymer is obtained by reacting a (meth) acrylate having an epoxy group with a carboxyl group in the copolymer, and the structural unit having a (meth) acryloyl group after the reaction is represented by the following formula (3 a).

[ solution 2]

In the formula (3a), R³⁰And R³¹Each independently is a hydrogen atom or a methyl group. a is an integer of 1 to 6. R³²Is a divalent group represented by the following formula (3a-1) or formula (3 a-2).

[ solution 3]

In the formula (3a-1), R³³Is a hydrogen atom or a methyl group. In the above formulae (3a-1) and (3a-2), ﹡ represents a site bonded to an oxygen atom. With respect to the structural unit represented by the formula (3a), for example, when a compound such as glycidyl methacrylate or 2-methylglycidyl methacrylate is reacted with a copolymer having a carboxyl group, R in the formula (3a)³²To form the formula (3 a-1). On the other hand, when a compound such as 3, 4-epoxycyclohexylmethyl methacrylate is reacted, R in the formula (3a)³²To form the formula (3 a-2).

The weight average molecular weight (Mw) of the polymer [ a ] is usually 1,000 to 100,000, preferably 3,000 to 50,000. Mw is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (dissolution solvent: tetrahydrofuran).

The polymer [ a ] is more preferably a resin having an ethylenically unsaturated group and a carboxyl group, which has a structural site represented by the following formula (3 b). By having an ethylenically unsaturated group and a carboxyl group, the polymerizability of the ethylenically unsaturated group and the alkali developability of the carboxyl group can be both achieved at a high level, and thus the sensitivity and developability can be both achieved at a high level.

[ solution 4]

(in the formula (3b), R⁴⁰Represents a divalent hydrocarbon group, R⁴¹Represents a hydrogen atom or a methyl group. Indicates a bonding site)

Specific examples of resins having an ethylenically unsaturated group and a carboxyl group and having a structural site represented by the formula (3b) are shown below.

As the resin having the structural site represented by formula (3b), an acid-modified epoxy (meth) acrylate resin can be preferably used. Examples thereof include: acid-modified cresol novolak-type epoxy (meth) acrylate resin, phenol novolak-type epoxy (meth) acrylate resin, bisphenol a-type epoxy (meth) acrylate resin, bisphenol F-type epoxy (meth) acrylate resin, biphenyl-type epoxy (meth) acrylate resin, and triphenylolmethane-type epoxy (meth) acrylate resin.

Examples of the acid-modified cresol novolak-type epoxy (meth) acrylate resin include polymers represented by the following formula (1). The acid-modified cresol novolac type epoxy (meth) acrylate resin can be obtained by reacting an acid anhydride such as phthalic anhydride or 1,2,3, 6-tetrahydrophthalic anhydride which is soluble in alkali with an epoxy (meth) acrylate resin obtained by reacting (meth) acrylic acid with a cresol novolac type epoxy resin.

The acid-modified cresol novolac epoxy (meth) acrylate resin can form a cured film having excellent hardness, solvent resistance, and heat resistance, even when cured and calcined at low temperatures, by having the rigid main chain skeleton, ethylenic unsaturated group, and carboxyl group of the cresol novolac epoxy resin.

[ solution 5]

In the formula (3c), b and c independently represent an integer of 1 to 30.

As a specific example of the acid-modified cresol novolak-type epoxy (meth) acrylate resin, CCR-1171H, CCR-1291H, CCR-1307H, CCR-1309H (manufactured by Nippon chemical Co., Ltd.) can be used.

[a] The acid value of the polymer is, for example, from 10mgKOH/g to 200mgKOH/g, preferably from 30mgKOH/g to 270mgKOH/g, and more preferably from 50mgKOH/g to 250 mgKOH/g. The acid value represents the number of mg of KOH required for neutralizing 1g of the solid content of the alkali-soluble resin.

[a] The weight average molecular weight (Mw) of the polymer is usually 1,000 to 100,000, preferably 3,000 to 50,000. Mw is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (dissolution solvent: tetrahydrofuran).

Polymers having an epoxy group as a polymerizable group may also be used. Such a polymer [ a ] can be obtained by radical polymerization using an epoxy group-containing unsaturated compound as a monomer, suitably together with other monomers such as methacrylic acid and acrylic acid. Examples of the epoxy group-containing unsaturated compound include unsaturated compounds containing an oxetanyl group (1, 2-epoxy structure), an oxetanyl group (1, 3-epoxy structure) and the like.

Examples of the unsaturated compound having an oxetanyl group include glycidyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, 3, 4-epoxybutyl acrylate, 3, 4-epoxybutyl methacrylate, 6, 7-epoxyheptyl acrylate, 6, 7-epoxyheptyl methacrylate, α -6, 7-epoxyheptyl ethacrylate, 3, 4-epoxycyclohexyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether and the like.

Examples of the unsaturated compound having an oxetanyl group include: 3- (methacryloyloxymethyl) oxetane, 3- (methacryloyloxymethyl) -2-methyloxetane, 3- (methacryloyloxymethyl) -3-ethyloxetane, 3- (methacryloyloxymethyl) -2-phenyloxetane, 3- (2-methacryloyloxyethyl) oxetane, 3- (2-methacryloyloxyethyl) -2-ethyloxetane, 3- (2-methacryloyloxyethyl) -3-ethyloxetane, 3- (2-methacryloyloxyethyl) -2-phenyloxetane, and methacrylates such as 2-difluorooxetane.

Among these epoxy group-containing unsaturated compounds, glycidyl methacrylate, 3, 4-epoxycyclohexyl methacrylate, and 3- (methacryloyloxymethyl) -3-ethyloxetane are preferable from the viewpoint of polymerizability.

The content of the [ a ] polymer in the curable composition is usually 30% by mass or more, preferably 40% by mass or more, per 100% by mass of the solid content of the composition, and the upper limit of the content of the [ a ] polymer is usually 90% by mass, in one embodiment 70% by mass or 60% by mass, per 100% by mass of the solid content of the composition.

By adopting such an embodiment, the alkali developability, the storage stability of the composition, the pattern shape, and the chromaticity characteristics can be improved in addition to further improvement in the luminance. The solid component is a total component other than the solvent.

[ B ] photosensitizer

The curable composition contains [ B ] a photosensitizer. The radiation sensitivity of the curable composition can be further improved. [B] The photosensitizers may be used alone or in combination of two or more.

Examples of the [ B ] sensitizer include a radiation-sensitive radical polymerization initiator, a radiation-sensitive acid generator, a radiation-sensitive base generator, and a combination thereof.

The radiation-sensitive radical polymerization initiator can accelerate the curing reaction of the curable composition by radiation when the compound [ A ] having a polymerizable group has an ethylenically unsaturated group such as a (meth) acryloyl group or a vinyl group.

Examples of the radiation-sensitive radical polymerization initiator include compounds which can generate active species capable of initiating a radical polymerization reaction of the compound having a polymerizable group [ A ] by exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray.

Specific examples of the radiation-sensitive radical polymerization initiator include O-acyloxime compounds, α -aminoketone compounds, α -hydroxyketone compounds, and acylphosphine oxide compounds.

Examples of the O-acyloxime compound include: 1- [ 9-ethyl-6- (2-methylbenzoyl) -9.h. -carbazol-3-yl ] -ethane-1-ketoxime-O-acetate, 1- [ 9-ethyl-6-benzoyl-9. h. -carbazol-3-yl ] -octane-1-ketoxime-O-acetate, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9.h. -carbazol-3-yl ] -ethane-1-ketoxime-O-benzoate, 1- [ 9-n-butyl-6- (2-ethylbenzoyl) -9.h. -carbazol-3-yl ] -ethane-1-ketoxime-O-benzoate Esters, ethanones, 1- [ 9-ethyl-6- (2-methyl-4-tetrahydrofurylbenzoyl) -9.h. -carbazol-3-yl ] -,1- (O-acetyloxime), ethanones, 1- [ 9-ethyl-6- (2-methyl-4-tetrahydropyranoylbenzoyl) -9.h. -carbazol-3-yl ] -,1- (O-acetyloxime), ethanones, 1- [ 9-ethyl-6- (2-methyl-5-tetrahydrofurylbenzoyl) -9.h. -carbazol-3-yl ] -,1- (O-acetyloxime), ethanones, 1- [ 9-ethyl-6- { 2-methyl-4- (2, 2-dimethyl-1, 3-dioxolanyl) methoxybenzoyl } -9.H. -carbazol-3-yl ] -,1- (O-acetyl oxime), ethanone, 1- [ 9-ethyl-6- (2-methyl-4-tetrahydrofuranylmethoxybenzoyl) -9.H. -carbazol-3-yl ] -,1- (O-acetyl oxime), 1, 2-octanedione, 1- [4- (phenylthio) -,2- (O-benzoyl oxime) ], and the like.

Examples of the α -aminoketone compound include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one, and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one.

Examples of the α -hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) one, and 1-hydroxycyclohexyl phenyl ketone.

Examples of the acylphosphine oxide compound include: 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, and the like.

The radiation-sensitive radical polymerization initiator is preferably a radical polymerization initiator containing a condensation ring from the viewpoint of enhancing the interaction with TADF and further promoting the hardening reaction by radiation, and specific examples of the condensation ring include naphthalene, anthracene, fluorene, indole, carbazole, benzimidazole, and among these, carbazolyl group derived from carbazole, substituted or unsubstituted 1,2,3, 4-tetrahydro-9-carbazolyl group are particularly preferable, and as the radical polymerization initiator containing a condensation ring, O-acyloxime compound and α -aminoketone compound are preferable, and 1- [ 9-ethyl-6- (2-methylbenzoyl) -9.h ] -carbazol-3-yl ] -ethane-1-ketoxime-O-acetate is preferable.

When the curable composition contains a radiation-sensitive radical polymerization initiator, the lower limit of the content of the radiation-sensitive radical polymerization initiator is preferably 0.5 part by mass, more preferably 1.0 part by mass, and still more preferably 1.5 parts by mass, based on 100 parts by mass of the compound having a polymerizable group [ a ]. The upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, and still more preferably 10 parts by mass, based on 100 parts by mass of the compound having a polymerizable group [ a ]. By setting the content to the above range, the curing reaction by radiation can be further promoted.

Specific examples of the radiation-sensitive acid generator include: iodonium salt-based radiation-sensitive acid generators, sulfonium salt-based radiation-sensitive acid generators, tetrahydrothiophenium salt-based radiation-sensitive acid generators, imide sulfonate-based radiation-sensitive acid generators, oxime sulfonate-based radiation-sensitive acid generators, quinone diazide compounds, and the like.

Examples of the iodonium salt-based radiation-sensitive acid generator include: diphenyliodonium trifluoromethanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, diphenyliodonium nonafluoro-n-butane sulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium dodecylbenzenesulfonate and the like.

Examples of the sulfonium salt-based radiation-sensitive acid generator include: triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, (hydroxyphenyl) benzylsulfonium toluenesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dicyclohexyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dimethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, triphenylsulfonium camphorsulfonate, (4-hydroxyphenyl) benzylsulfonium toluenesulfonate, 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, etc.

Examples of the tetrahydrothiophenium salt-based radiation-sensitive acid generator include: 4-hydroxy-1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate, 4-methoxy-1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate, 4-ethoxy-1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate, 4-methoxymethoxy-1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate, 4-ethoxymethoxy-1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate, 4- (1-methoxyethoxy) -1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate, 4- (2-methoxyethoxy) -1-naphthyl tetrahydrothiophenium trifluoromethanesulfonate and the like.

Examples of the imide sulfonate-based radiation-sensitive acid generator include: trifluoromethylsulfonyloxy bicyclo [2.2.1] hept-5-enedicarboximide, succinimide triflate, phthalimide triflate, N-hydroxynaphthalimide methanesulfonate, N-hydroxy-5-norbornene-2, 3-dicarboximide propanesulfonate and the like.

Examples of the oxime sulfonate-based radiation-sensitive acid generator include: (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene) - (2-methylphenyl) acetonitrile, (5-octylsulfonyloxyimino-5H-thiophen-2-ylidene) - (2-methylphenyl) acetonitrile, (camphorsulfonyloxyimino-5H-thiophen-2-ylidene) - (2-methylphenyl) acetonitrile, (5-p-toluenesulfonyloxyimino-5H-thiophen-2-ylidene) - (2-methylphenyl) acetonitrile, (5-octylsulfonyloxyimino) - (4-methoxyphenyl) acetonitrile and the like.

Examples of the quinone diazide compound include: 1, 2-naphthoquinone diazide sulfonate ester of trihydroxybenzophenone, 1, 2-naphthoquinone diazide sulfonate ester of tetrahydroxybenzophenone, 1, 2-naphthoquinone diazide sulfonate ester of pentahydroxybenzophenone, 1, 2-naphthoquinone diazide sulfonate ester of hexahydroxybenzophenone, 1, 2-naphthoquinone diazide sulfonate ester of (polyhydroxyphenyl) alkane, and the like.

Examples of the 1, 2-naphthoquinone diazide sulfonate of the trihydroxybenzophenone include: 2,3, 4-trihydroxybenzophenone-1, 2-naphthoquinone diazide-4-sulfonate, 2,3, 4-trihydroxybenzophenone-1, 2-naphthoquinone diazide-5-sulfonate, 2,4, 6-trihydroxybenzophenone-1, 2-naphthoquinone diazide-4-sulfonate, 2,4, 6-trihydroxybenzophenone-1, 2-naphthoquinone diazide-5-sulfonate, and the like.

Examples of the 1, 2-naphthoquinone diazide sulfonate of tetrahydroxybenzophenone include: 2,2',4,4' -tetrahydroxybenzophenone-1, 2-naphthoquinone diazide-4-sulfonate, 2',4,4' -tetrahydroxybenzophenone-1, 2-naphthoquinone diazide-5-sulfonate, 2,3,4,3' -tetrahydroxybenzophenone-1, 2-naphthoquinone diazide-4-sulfonate, 2,3,4,4' -tetrahydroxy-3 ' -methoxybenzophenone-1, 2-naphthoquinone diazide-5-sulfonate, and the like.

Examples of the 1, 2-naphthoquinone diazide sulfonate of the pentahydroxybenzophenone include: 2,3,4,2',6' -pentahydroxybenzophenone-1, 2-naphthoquinonediazide-4-sulfonate, 2,3,4,2',6' -pentahydroxybenzophenone-1, 2-naphthoquinonediazide-5-sulfonate and the like.

Examples of the 1, 2-naphthoquinone diazide sulfonate ester of hexahydroxybenzophenone include: 2,4,6,3',4',5' -hexahydroxybenzophenone-1, 2-naphthoquinone diazide-4-sulfonate, 2,4,6,3',4',5' -hexahydroxybenzophenone-1, 2-naphthoquinone diazide-5-sulfonate, 3,4,5,3',4',5' -hexahydroxybenzophenone-1, 2-naphthoquinone diazide-4-sulfonate, and the like.

Examples of the 1, 2-naphthoquinone diazide sulfonate of the (polyhydroxyphenyl) alkane include: bis (2, 4-dihydroxyphenyl) methane-1, 2-naphthoquinone diazide-4-sulfonate, bis (2, 4-dihydroxyphenyl) methane-1, 2-naphthoquinone diazide-5-sulfonate, bis (p-hydroxyphenyl) methane-1, 2-naphthoquinone diazide-4-sulfonate, and the like.

The radiation-sensitive acid generator is preferably an oxime sulfonate radiation-sensitive acid generator and a quinone diazide compound, and more preferably (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene) - (2-methylphenyl) acetonitrile or 1,1, 1-tris (p-hydroxyphenyl) ethane-1, 2-naphthoquinone diazide-5-sulfonate.

Specific examples of the radiation-sensitive base generator include:

a radiation-sensitive base generator containing a heterocyclic group such as 4- (methylthiobenzoyl) -1-methyl-1-morpholinoethane, (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, N- (2-nitrobenzyloxycarbonyl) pyrrolidine, and 1- (anthraquinone-2-yl) ethylimidazolium carboxylate;

2-nitrobenzylcyclohexylcyclohexylcarbamate, [ [ (2, 6-dinitrobenzyl) oxy ] carbonyl ] cyclohexylamine, bis [ [ (2-nitrobenzyl) oxy ] carbonyl ] hexane-1, 6-diamine, triphenylmethanol, o-carbamoylhydroxyamide, o-carbamoyloxime, hexaamminocobalt (III) tris (triphenylmethylborate), 1, 2-dicyclohexyl-4, 4,5, 5-tetramethylbiguanide n-butyltriphenylborate, and the like, from the viewpoint of further promoting the thiolation reaction of the [ B ] compound, 1, 2-dicyclohexyl-4, 4,5, 5-tetramethylbiguanide n-butyltriphenylborate is preferable.

When the curable composition contains the [ B ] sensitizer, the lower limit of the content of the [ B ] sensitizer is preferably 0.5 parts by mass, more preferably 1.0 part by mass, per 100 parts by mass of the [ A ] compound having a polymerizable group. The upper limit of the content is preferably 30 parts by mass, and more preferably 25 parts by mass, based on 100 parts by mass of the compound having a polymerizable group [ a ]. By setting the content to the above range, the radiation sensitivity of the curable composition can be further improved.

[C] Thermally active delayed fluorescence compound

Thermally active Delayed Fluorescence (also referred to as TADF) is Fluorescence having the same spectrum as normal Fluorescence but a longer lifetime than normal Fluorescence. The delayed fluorescence material refers to a material that emits such delayed fluorescence. The lifetime of delayed fluorescence emitted from the delayed fluorescent material varies depending on the type of the delayed fluorescent material, and is, for example, 1. mu.s or more, 5. mu.s or more, or 10. mu.s or more.

In the present invention, a delayed fluorescent material having such properties is selected and used as a light emitting material. The mechanism of delayed fluorescence emission of the delayed fluorescent material used in the present invention is not particularly limited. The delayed fluorescence includes fluorescence emitted by reverse intersystem crossing (intersystem crossing) from an excited triplet state to an excited singlet state, but the reverse intersystem crossing may be caused by triplet-triplet annihilation or by absorption of thermal energy. In addition, delayed fluorescence may be delayed fluorescence in which exciplex (exiplex) participates. The delayed fluorescent material used in the present invention is preferably a thermally active delayed fluorescent material activated by heat.

In the present invention, as the light-emitting material, only a delayed fluorescence material may be used, or a delayed fluorescence material and a light-emitting material that does not emit delayed fluorescence may be used in combination. An embodiment using only delayed fluorescence material is preferred. The delayed fluorescence material used as the light-emitting material of the present invention may be only one type or a mixture of two or more types.

As a delayed fluorescence material that can be used in the present invention, for example, a compound having a structure represented by the following general formula (1) is cited as a preferable specific example.

In the general formula (1) and the general formula (2), R¹To R⁷Represents a cyano group. In the case where either is cyano, it may be R¹To R³Any one of them. When any two are cyano groups, R may be exemplified¹And R³Or R²And R⁴Combinations of (a) and (b). When any three are cyano groups, R may be exemplified¹And R³And R⁴Combinations of (a) and (b).

In the general formula (1) and the general formula (2), R¹To R⁷At least one of them represents a group represented by the following general formula (X). When two or more groups represented by the general formula (X) are present, these groups may be the same or different, and more preferably are the same.

[ solution 6]

In the general formula (X), R²¹To R²⁸Each independently represents a hydrogen atom or a substituent. Wherein at least one of < A > or < B > described below is satisfied. More preferably, both are satisfied.

＜A＞R²⁵And R²⁶Together form a single bond.

＜B＞R²⁷And R²⁸Represent the groups of atoms required to form together a substituted or unsubstituted benzene ring.

The group represented by the general formula (X) is preferably a substituted or unsubstituted 9-carbazolyl group, a substituted or unsubstituted 1,2,3, 4-tetrahydro-9-carbazolyl group, a 3, 6-di (tert-butyl) -9-carbazolyl group, a substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group. Namely, R in the general formula (1) or (2)¹To R⁷Any of which is preferably a substituted or unsubstituted 9-carbazolyl group, a substituted or unsubstituted 1,2,3, 4-tetrahydro-9-carbazolyl group, a substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group. More preferably R of the formula (1)¹To R⁵Any two or more of which are substituted or unsubstituted 9-carbazolyl, substituted or unsubstitutedSubstituted 1,2,3, 4-tetrahydro-9-carbazolyl, substituted or unsubstituted 1-indolyl, or substituted or unsubstituted diarylamino.

The group represented by the general formula (X) is particularly preferably a substituted or unsubstituted 9-carbazolyl group or 3, 6-di (tert-butyl) -9-carbazolyl group.

R as formula (X)²¹To R²⁸Examples thereof include: hydroxyl, halogen atom, cyano, alkyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, alkylthio group having 1 to 20 carbon atoms, alkyl-substituted amino group having 1 to 20 carbon atoms, acyl group having 2 to 20 carbon atoms, aryl group having 6 to 40 carbon atoms, heteroaryl group having 3 to 40 carbon atoms, diarylamino group having 12 to 40 carbon atoms, substituted or unsubstituted carbazolyl group having 12 to 40 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkynyl group having 2 to 10 carbon atoms, alkoxycarbonyl group having 2 to 10 carbon atoms, alkylsulfonyl group having 1 to 10 carbon atoms, haloalkyl group having 1 to 10 carbon atoms, amide group, alkylamide group having 2 to 10 carbon atoms, trialkylsilyl group having 3 to 20 carbon atoms, trialkylsilylalkyl group having 4 to 20 carbon atoms, trialkylsilylkenyl group having 5 to 20 carbon atoms, trialkylsilylkynyl group having 5 to 20 carbon atoms, nitro group, and the like. In these embodiments, those capable of further substitution with a substituent may be substituted. More preferred substituents are halogen atoms, cyano groups, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 40 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 40 carbon atoms, substituted or unsubstituted diarylamino groups having 12 to 40 carbon atoms, and substituted or unsubstituted carbazolyl groups having 12 to 40 carbon atoms. Further preferred substituents are fluorine atom, chlorine atom, cyano group, C1-10 substituted or unsubstituted alkyl group, C1-10 substituted or unsubstituted alkoxy group, C1-10 substituted or unsubstituted dialkylamino group, C6-15 substituted or unsubstituted aryl group, and C3-12 substituted or unsubstituted heteroaryl group.

The alkyl group in the present specification may be any of a straight chain, a branched chain and a cyclic group, and more preferably has 1 to 6 carbon atoms, and specific examples thereof include: methyl, ethyl, propyl, butyl, tert-butyl, pentyl, hexyl, isopropyl. The alkoxy group may be linear, branched or cyclic, and more preferably has 1 to 6 carbon atoms, and specific examples thereof include: methoxy, ethoxy, propoxy, butoxy, tert-butoxy, pentoxy, hexoxy, isopropoxy. The two alkyl groups of the dialkylamino group may be the same or different from each other, and are preferably the same. The two alkyl groups of the dialkylamino group may be each independently any of a straight chain, a branched chain, and a cyclic group, and more preferably have 1 to 6 carbon atoms, and specific examples thereof include: methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl. The aryl group may be a monocyclic ring or a condensed ring, and specific examples thereof include a phenyl group and a naphthyl group. The heteroaryl group may be a monocyclic ring or a condensed ring, and specific examples thereof include: pyridyl, pyridazinyl, pyrimidinyl, triazinyl, triazolyl, benzotriazolyl. These heteroaryl groups may be groups bonded via a heteroatom or may be groups bonded via carbon atoms constituting the heteroaryl ring.

In the general formula (1) and the general formula (2), R is¹To R⁷When any one of them is a group represented by the general formula (X), R may be¹To R³Any one of them. When any two of the groups are represented by the general formula (X), R may be exemplified¹And R³Or R²And R⁴Combinations of (a) and (b). In the case where any three groups are represented by the general formula (X), R may be exemplified¹And R³And R⁴Combinations of (a) and (b).

Any of the two ortho-positions of the benzene ring to which the group represented by the general formula (X) is bonded is preferably a cyano group. Both ortho-positions may also be cyano. In addition, when two or more groups represented by the general formula (X) are bonded to the benzene ring, it is preferable that at least two of these satisfy the condition that any one of the two ortho-positions of the benzene ring to which the group represented by the general formula (X) is bonded is a cyano group.

In the general formula (1) and the general formula (2), R¹To R⁷At least one of which represents cyano, R¹To R⁷At least one of them represents a group represented by the general formula (X), and the rest R¹To R⁷May represent a hydrogen atom or a substituent.

As R¹To R⁷Preferable substituents include, for example: hydroxyl, halogen atom, alkyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, alkylthio group having 1 to 20 carbon atoms, alkyl-substituted amino group having 1 to 20 carbon atoms, acyl group having 2 to 20 carbon atoms, aryl group having 6 to 40 carbon atoms, heteroaryl group having 3 to 40 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkynyl group having 2 to 10 carbon atoms, alkoxycarbonyl group having 2 to 10 carbon atoms, alkylsulfonyl group having 1 to 10 carbon atoms, amido group, alkylamido group having 2 to 10 carbon atoms, trialkylsilyl group having 3 to 20 carbon atoms, trialkylsilylalkyl group having 4 to 20 carbon atoms, trialkylsilylkenyl group having 5 to 20 carbon atoms, trialkylsilylkynyl group having 5 to 20 carbon atoms, nitro group, and the like. In these embodiments, those capable of further substitution with a substituent may be substituted. More preferred substituents are hydroxyl, halogen atom, substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted dialkylamino group having 1 to 20 carbon atoms, substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and substituted or unsubstituted heteroaryl group having 3 to 40 carbon atoms. Further preferred substituents are hydroxyl, fluorine, chlorine, C1-10 substituted or unsubstituted alkyl, C1-10 substituted or unsubstituted alkoxy, C1-10 substituted or unsubstituted dialkylamino, C6-15 substituted or unsubstituted aryl, and C3-12 substituted or unsubstituted heteroaryl. Further, hydroxyl group, fluorine atom, chlorine atom are more preferable.

In the general formula (1) and the general formula (2), R¹To R⁷Among them, three or less, more preferably two or less, still more preferably one or less, and further preferably 0.

Preferable specific examples of the compound include compounds represented by the following formulae (4), (5), (6) and (7). In the formula (7), tBu represents a tert-butyl group.

[ solution 7]

In the curable composition, the content of the [ C ] thermally active delayed fluorescence compound is in the range of 0.01 to 5, and more preferably in the range of 0.05 to 1, relative to the total content of the [ B ] sensitizer. When the amount is in the above range, a cured film having excellent solvent resistance can be formed while the radiation sensitivity of the cured film formation is improved.

The curable composition may contain a solvent in addition to the above components. If the curable composition contains a solvent, the coatability is improved. The solvent is not particularly limited as long as the above-mentioned components can be dissolved or dispersed, and examples thereof include solvents used in the synthesis of the above-mentioned [ a ] polymer. The solvent may be used alone or in combination of two or more.

[ other ingredients ]

The curable composition may contain other components such as other polymers or additives within a range not impairing the object of the present invention. Examples of the other components include: surfactants, fillers such as inorganic particles, antioxidants, ultraviolet absorbers, and polymers such as polyimide. The content of these additives may be appropriately selected within a range not prejudicial to the object of the present invention.

The curable composition can be prepared by a suitable method, and for example, can be prepared by mixing [ A ] a compound having a polymerizable group, [ B ] a compound, and optionally an optional component in a solvent. The lower limit of the concentration of the solid content in the composition at the time of mixing is preferably 5% by mass, and more preferably 10% by mass. The upper limit of the concentration is preferably 50% by mass, and more preferably 40% by mass. By setting the solid content concentration in the above range, the coatability can be improved. In the present specification, the term "solid content" refers to a residual content obtained by drying a sample on a 175 ℃ hot plate for 1 hour to remove volatile substances.

< hard coating >

The cured film is obtained from the curable composition. Examples of the cured film include: protective films, interlayer insulating films, planarization films, and the like. The cured film is obtained from the curable composition, and therefore has high hardness and excellent solvent resistance. The method for forming the cured film is not particularly limited, and a method for forming a cured film described later is preferably applied.

< display element >

The display element has the hardening film. That is, the hardened film can be preferably used for a display element. Examples of the display element include: liquid crystal display elements, organic EL elements, electronic paper elements, and the like. Since the display element has the cured film having high hardness and excellent solvent resistance, for example, yield can be improved and durability can be improved.

< method for Forming hardened film >

The method for forming the hardened film comprises the following steps: a step of forming a coating film from the curable composition (hereinafter, also referred to as a "coating film forming step"), a step of irradiating (exposing) at least a part of the coating film with radiation (hereinafter, also referred to as a "radiation irradiating step"), a step of developing the coating film irradiated with the radiation (hereinafter, also referred to as a "developing step"), and a step of heating the developed coating film (hereinafter, also referred to as a "heating step"). The method of forming a cured film may further include a step of heating the coating film irradiated with the radiation between the radiation irradiation step and the development step (hereinafter, also referred to as a "Post Exposure Bake (PEB) step") as an arbitrary step.

According to the method for forming a cured film, a cured film having high hardness and excellent solvent resistance can be easily and efficiently formed by using the curable composition. Hereinafter, each step will be explained.

[ coating film Forming Process ]

In this step, after the curable composition is applied to a surface on which a cured film is formed, such as a substrate surface, the applied surface is preferably heated (prebaked) to remove the solvent and the like, thereby forming a coating film. Examples of the material of the substrate include: glass, quartz, silicon, resin, etc. Specific examples of the resin include: polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, polyimide, an addition polymer of a cyclic olefin, a ring-opening polymer of a cyclic olefin, a hydride thereof, and the like.

The method for applying the curable composition is not particularly limited, and for example, the following can be used: a spraying method, a roll coating method, a spin coating method (spin coat method), a slit die coating method, a bar coating method, and the like. Among these coating methods, spin coating and slit die coating are particularly preferable. The conditions for the prebaking may vary depending on the kind of each component, the blending ratio, and the like, and may be set to a temperature of 70 ℃ to 130 ℃ inclusive, or a heating time of 1 minute to 10 minutes inclusive, for example.

[ radiation Exposure Process ]

In this step, a part of the coating film formed in the coating film forming step is irradiated with radiation. In general, when a part of the coating film is irradiated with radiation, the radiation is irradiated through a photomask having a predetermined pattern. As the radiation, for example, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray, or the like can be used. Of these radiations, radiation having a wavelength in the range of 190nm to 450nm is preferable, and radiation including ultraviolet rays of 365nm is more preferable.

The lower limit of the exposure amount in this step is preferably a value obtained by measuring the intensity of radiation at a wavelength of 365nm with an illuminometer ("OAI model 356" by OAI optical Associates Inc.), and is preferably 10mJ/cm²More preferably 20mJ/cm². The upper limit of the exposure amount is preferably 2,000mJ/cm in a value measured by the illuminometer²More preferably 1,000mJ/cm²。

[ developing Process ]

In this step, the coating film after the irradiation with the radiation is developed with a developer to form a predetermined pattern. The developer is preferably an alkaline developer. Examples of the alkaline developing solution include an alkaline aqueous solution in which at least one of alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, tetramethylammonium hydroxide, and tetraethylammonium hydroxide is dissolved. In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant may be added to the alkaline developer.

As the developing method, for example, a suitable method such as a liquid coating method, a dipping method, a shaking dipping method, a spraying method, or the like can be used. The developing time varies depending on the composition of the curable composition, and is, for example, 10 seconds to 180 seconds. After such a development treatment, for example, a water-flowing cleaning is performed for a treatment time of 30 seconds to 90 seconds, and then, for example, air-drying is performed by using compressed air or compressed nitrogen gas, whereby a desired pattern can be formed.

[ heating Process ]

In this step, the coating film patterned by development is heated (post-baked) using a heating device such as a hot plate or an oven, thereby obtaining a cured film having a desired pattern. The lower limit of the heating temperature is preferably 80 ℃, more preferably 120 ℃, and still more preferably 150 ℃. The heating time varies depending on the type of heating equipment, and for example, in the case of heating on a hot plate, it may be set to 5 minutes or more and 30 minutes or less, and in the case of heating in an oven, it may be set to 10 minutes or more and 90 minutes or less. The heating may be performed in air, or in an inert gas atmosphere such as nitrogen or argon. In addition, a step baking method in which the heating step is performed twice or more can also be used. The average thickness of the hardened film formed in this manner is, for example, 0.1 μm or more and 10 μm or less. The sequence of the exposure or heating process may also be different.

[ examples ]

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples.

[ weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) ]

Mw and Mn were measured by Gel Permeation Chromatography (GPC) under the following conditions. The molecular weight distribution (Mw/Mn) was calculated from the Mw and Mn thus obtained.

The device comprises the following steps: "GPC-101" by Showa electrician corporation "

Pipe column: the components are "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" of Showa Denko K.K..

Mobile phase: tetrahydrofuran (THF)

Temperature of the pipe column: 40 deg.C

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μ L

A detector: differential refractometer

Standard substance: monodisperse polystyrene

[ hydrogen Nuclear Magnetic Resonance (NMR) ((II))¹H-nuclear magnetic resonance，¹H-NMR) analysis]

¹H-NMR analysis was carried out using a nuclear magnetic resonance apparatus ("ECX 400P" from Japan Electron Ltd.).

< Synthesis of Polymer >

Synthesis example 1 Synthesis of Polymer (A-1)

Into a flask equipped with a cooling tube and a stirrer, 11 parts by mass of 2,2' -azobis (2, 4-dimethylvaleronitrile) and 300 parts by mass of propylene glycol monomethyl ether were charged. Then, 75 parts by mass of methacrylic acid and 25 parts by mass of benzyl methacrylate were charged, nitrogen gas was replaced, and the solution was heated to 70 ℃ with slow stirring, and the temperature was maintained for 5 hours to carry out polymerization. After that, the solution was stirred at 100 ℃ for 1 hour, and then returned to room temperature. Then, 50 parts by mass of glycidyl methacrylate and 2 parts by mass of tetrabutylammonium bromide were put in, and the temperature of the solution was raised to 90 ℃ and maintained for 9 hours to effect a reaction. Thus, a polymer solution containing the polymer (A-1) having a methacryloyl group in the side chain was obtained. The polymer solution had a solid content concentration of 23.0% by mass, the Mw of the polymer (A-1) was 11,000, and the molecular weight distribution (Mw/Mn) was 2.0.

Synthesis example 2 Synthesis of Polymer (A-2)

200 parts of cresol novolak type epoxy resin "EOCN-1020" (manufactured by Nippon chemical Co., Ltd., epoxy equivalent 200) and 245 parts of propylene glycol monomethyl ether acetate were put into a flask equipped with a cooling tube and a stirrer, and heated to 110 ℃ to be uniformly dissolved. Then, 76 parts (1.07 parts by mole) of acrylic acid, 2 parts of triphenylphosphine, and 0.2 part of p-methoxyphenol were charged, and the mixture was reacted at 110 ℃ for 10 hours. 91 parts (0.60 parts by mole) of tetrahydrophthalic anhydride was further added to the reaction product, and the mixture was reacted at 90 ℃ for 5 hours, followed by cooling, and then propylene glycol monomethyl ether acetate was added to adjust the solid content, thereby obtaining a propylene glycol monomethyl ether acetate solution (solid content: 25%) of a polymer (A-2) (Mn: 2,200) having a carboxyl group and an acryloyl group.

Synthesis example 4 Synthesis of Polymer (A-6)

7 parts by mass of 2,2' -azobis (2, 4-dimethylvaleronitrile) and 200 parts by mass of diethylene glycol ethyl methyl ether were put into a flask equipped with a cooling tube and a stirrer. Then, 16 parts by mass of methacrylic acid and tricyclo [5.2.1.0 ] methacrylate were added^{2 ,6}]16 parts by mass of decan-8-yl ester, 38 parts by mass of methyl methacrylate, 10 parts by mass of styrene and 20 parts by mass of glycidyl methacrylate, the solution was purged with nitrogen, and then polymerization was carried out by raising the temperature of the solution to 70 ℃ while stirring slowly and maintaining the temperature for 4 hours to obtain a solution containing the polymer (a-6) (the solid content concentration: 34.4% by mass, Mw: 8,000, Mw/Mn: 2.3).

< preparation of curable composition, formation of cured film, and evaluation of physical Properties >

The following components used for the preparation of each curable composition are shown.

[ [ A ] component ]

A-1: polymer (A-1)

A-2: polymer (A-2)

A-3: fluorene diacrylate (Osaka gas chemical company, "OGSOL EA-0200")

A-4: tris (4-hydroxyphenyl) ethane triglycidyl ether

A-5: dipentaerythritol hexaacrylate (Kayarad DPHA from Japan chemical Co.)

A-6: polymer (A-6)

[B] [ radiation-sensitive radical polymerization initiator ]

B1-1: 1- [ 9-Ethyl-6- (2-methylbenzoyl) -9.H. -carbazol-3-yl ] -ethane-1-ketoxime-O-acetate ("Irgacure) OX 02" from BASF corporation)

B1-2: bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide (trade name "Irgacure 819", manufactured by BASF corporation)

B1-3: a mixture of 10 parts by mass of 2,2 '-bis (2, 4-dichlorophenyl) -4,4',5,5 '-tetraphenylbenzimidazole, 10 parts by mass of 4,4' -bis (dimethylamino) benzophenone and 5 parts by mass of 2-mercaptobenzothiazole

B1-4: 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) -butan-1-one (trade name "Irgacure 907", manufactured by BASF corporation)

[ radiation-sensitive acid generators ]

B2-1: (5-Propylsulfonyloxyimino-5H-thiophen-2-ylidene) - (2-methylphenyl) acetonitrile ("Irgacure (PAG) 103" by BASF corporation)

[ radioactivity-sensitive base-generating agent ]

B3-1: 1, 2-dicyclohexyl-4, 4,5, 5-tetramethylbiguanide n-butyltriphenylborate (Wako pure chemical industries, Ltd. "WPBG-300")

[ [ C ] component ]

C-1: compound (4)

C-2: compound (5)

C-3: compound (6)

C-4: compound (7)

[ solution 8]

[ example 1]

To Propylene Glycol Monomethyl Ether Acetate (PGMEA) (100 parts by mass in terms of solid content), polymer (a-1) as component [ a ], 10 parts by mass of (B1-1) as component [ B ], and 1 part by mass of (C-1) as component [ C ] were added, and 0.1 part by mass of SH 190 (manufactured by Toray Corning Silicone) as a surfactant was added, followed by mixing and stirring, and then filtration was performed using a 0.2 μm filter, thereby preparing a curable composition.

Examples 2 to 9 and comparative examples 1 to 2

Other than changing the kinds and blending amounts of the respective blending components as described in table 1 below, respective curable compositions were prepared in the same manner as in example 1. In Table 1, "-" indicates that no corresponding component was used.

The obtained respective curable compositions were evaluated according to the following methods. The evaluation results are shown in table 1.

[ storage stability ]

The storage stability was evaluated by measuring the time until the viscosity reached 10 times the viscosity immediately after the preparation when the curable composition was stored at 25 ℃. The viscosity was measured using an ELD viscometer available from Tokyo Meter at 25 ℃ and 20 rpm. The longer the time until the viscosity reaches 10 times the viscosity immediately after the preparation, the better the storage stability, and for example, in the case of 800 hours or more, the storage stability is evaluated as good. The results are shown in table 1.

[ hardness ]

Regarding the hardness, a hardened film formed from a hardening composition by the following forming method was evaluated using a pencil hardness meter in compliance with Japanese Industrial Standards (JIS) K5600-5-4 (1999). When the hardness is H or more, it can be evaluated as good. The results are shown in table 1.

(method of Forming cured film)

A curable composition was applied to an alkali-free glass substrate by a spinner, and then prebaked on a hot plate at 90 ℃ for 3 minutes to form a coating film having an average thickness of 3 μm. The obtained coating film was irradiated with a high-pressure mercury lamp at 300mJ/cm without using a photomask²The cumulative exposure dose of (2) exposure contains radiation of wavelengths of 365nm, 405nm and 436 nm. Then, it was heated in an oven at 150 ℃ for 30 minutes, thereby obtaining a hardened film.

[ solvent resistance ]

The solvent resistance of the cured film formed from the curable composition was evaluated by measuring the rate of change in the average thickness before and after immersion in acetone according to the following method. The formation of the cured film was performed by the same method as the evaluation of the hardness. The results are shown in table 1.

(method of measuring average thickness Change Rate)

The average thickness of the cured film after formation (T1) and the average thickness after 20 minutes of immersion in acetone (T2) were measured, and the rate of change was calculated by the following formula. When the rate of change in the average thickness is 5% or less, the solvent resistance is evaluated to be good.

Change rate (%) of average thickness { (T1-T2)/T1} × 100

[ sensitivity to radiation ]

The cured film formed from the curable composition was evaluated for radiation sensitivity based on the exposure amount when the hardness was H, which was measured using a pencil hardness meter in the same manner as the evaluation of the hardness. The method of forming the cured film was performed in the same manner as the evaluation of the hardness, except that the exposure amount was changed arbitrarily. Further, if the radiation sensitivity is 100mJ/cm²The following results were evaluated as good. The results are shown in table 1.

[ Table 1]

In the table, "-" indicates no addition.

As shown in the results in table 1, the curable composition of the present invention can form a cured film having high hardness and excellent solvent resistance even in a film obtained by a curing and baking process at 200 ℃.

Claims (10)

1. A curable composition comprising:

(A) a compound having a polymerizable group;

(B) a photosensitizer; and

(C) a thermally active delayed fluorescence compound.

2. The curable composition according to claim 1, wherein the (C) thermally active delayed fluorescence compound is a compound represented by the following formula (1) or formula (2),

in the formulae (1) and (2), R¹To R⁷At least one of them represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a phenyl group, a tolyl group, a naphthyl group, a cyano group, a group represented by the formula (X);

in the formula (X), R²¹To R²⁸Each independently represents a hydrogen atom or a substituent; wherein at least one of < A > or < B > is satisfied;

＜A＞R²⁵and R²⁶Together form a single bond;

＜B＞R²⁷and R²⁸Together form a substituted or unsubstituted benzene ring.

3. The curable composition according to claim 1 or 2, wherein: the formula (X) represents a 9-carbazolyl group, a 3, 6-di (tert-butyl) -9-carbazolyl group, a substituted or unsubstituted 1,2,3, 4-tetrahydro-9-carbazolyl group, a substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group.

4. The curable composition according to claim 1 or 2, wherein the polymerizable group of the compound (A) having a polymerizable group is at least one selected from the group consisting of an epoxy group, a vinyl group and a (meth) acryloyl group.

5. The curable composition according to claim 1 or 2, further comprising (D) a binder resin.

6. The curable composition according to claim 1 or 2, wherein the (B) sensitizer is at least one selected from the group consisting of an acid generator, a base generator, and a radical polymerization initiator.

7. The curable composition according to claim 1 or 2, wherein the sensitizer is further a radical polymerization initiator comprising a condensed ring.

8. The curable composition according to claim 1 or 2, wherein the content ratio of the (C) thermally active delayed fluorescence compound is in the range of 0.01 to 5 relative to the total content of the (B) sensitizer.

9. A method for forming a cured film, comprising the steps of:

(1) a step of forming a coating film of the curable composition according to any one of claims 1 to 8 on a substrate; and

(2) a step of exposing the coating film or a step of heating the coating film at 80 ℃ to 150 ℃.

10. A display element having a cured film obtained by the method for forming a cured film according to claim 9.